The present invention relates to data storage on flexible diskettes, and more particularly to apparatus for controlling the duplication of data stored on flexible diskettes.
There are a number of commercially available systems for copying magnetically encoded data stored on flexible diskettes, also known as "floppy disks". Such disks are similar in appearance to 45 RPM phonograph records, and typically include a small "index" hole at one radius. The prior art data duplication control systems usually operate by feeding the information stored on a master diskette to a computer, which also receives signals indicative of the speed and phase of the master disk. The computer then manipulates this information to electronically control the drive of one or more slave diskettes, which receive the bits to be copied from the master diskette. Such systems involve large, expensive data processing equipment, which represents a significant expense to the user.
Another technique which has been tried with very limited success is the mechanical coupling of the master and slave disk drives. This approach suffers the shortcoming that conventional disk drives operate within speed tolerances on the order of several percent, which introduces an inherent error in such mechanical coordination.
Accordingly, it is a principal object of the invention to provide simple, inexpensive apparatus for copying the information stored on flexible diskettes. A particular object is the provision of apparatus for this purpose which is relatively simple and of low cost.
Another object of the invention is the achievement of reliable data duplication, despite the normal error encountered in conventional diskette drives.
A further object is the design of data duplication apparatus which is compatible with conventional flexible diskette drives.